An image processing apparatus is known, which joins images of area around a vehicle in a plurality of direction to generate and display an overhead-view image, in which a region around the vehicle was viewed from, for example, above (for example, Japanese patent laid-open publications 2009-137353, 2007-41791, and 2007-36668). Such an overhead-view image is, for example, displayed on a display screen of a navigation system and is used by a driver for ensuring safety. Hence, the overhead-view image is required to include all objects in the region around the vehicle and to have a fine visibility.
To meet the above requirement, a plurality of imaging devices are equipped, for example, at front, rear, left, and right sections of the vehicle to take images in four directions, that is, front, rear, left, and right of the vehicle, of which equipping positions and angles of a pair of the imaging devices next to each other are adjusted so that imaging regions thereof overlap with each other to some extent. Thereby, all objects in the region around the vehicle are imaged without being missed.
In this case, the generated images have overlapping regions. Hence, such an image process is performed as to set a boundary between the two images at the overlapping regions, and the two images are joined along the boundary. However, imaging devices have production errors, therefore, it is difficult to match the optical properties of the adjacent imaging devices. Hence, the images have discontinuity around the boundaries. Hence, there is proposed a method for making the discontinuity of the image less outstanding to avoid deterioration of the visibility. For example, there is an imaging method such as to make the images translucent and overlap with each other around the boundaries.
However, if images of a single object from different angles overlap with each other, the object could be displayed double. Then, for example, when there is an object which is subject to a collision-avoidance operation around the boundaries, the object being displayed double possibly causes confusion for the driver. Such confusion is not preferable for the safety.